# The MIT License (MIT)
#
# Copyright (c) 2017 Dean Miller for Adafruit Industries
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

from micropython import const
# from adafruit_bus_device.i2c_device import I2CDevice

# __version__ = "0.0.0-auto.0"
# __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_INA219.git"

# # Bits
# # pylint: disable=bad-whitespace
# _READ = const(0x01)

# Config Register (R/W)
_REG_CONFIG = const(0x00)
_CONFIG_RESET = const(0x8000)  # Reset Bit

_CONFIG_BVOLTAGERANGE_MASK = const(0x2000)  # Bus Voltage Range Mask
_CONFIG_BVOLTAGERANGE_16V = const(0x0000)  # 0-16V Range
_CONFIG_BVOLTAGERANGE_32V = const(0x2000)  # 0-32V Range

_CONFIG_GAIN_MASK = const(0x1800)     # Gain Mask
_CONFIG_GAIN_1_40MV = const(0x0000)   # Gain 1, 40mV Range
_CONFIG_GAIN_2_80MV = const(0x0800)   # Gain 2, 80mV Range
_CONFIG_GAIN_4_160MV = const(0x1000)  # Gain 4, 160mV Range
_CONFIG_GAIN_8_320MV = const(0x1800)  # Gain 8, 320mV Range

# _CONFIG_BADCRES_MASK = const(0x0780)   # Bus ADC Resolution Mask
# _CONFIG_BADCRES_9BIT = const(0x0000)   # 9-bit bus res = 0..511
# _CONFIG_BADCRES_10BIT = const(0x0080)  # 10-bit bus res = 0..1023
# _CONFIG_BADCRES_11BIT = const(0x0100)  # 11-bit bus res = 0..2047
# _CONFIG_BADCRES_12BIT = const(0x0180)  # 12-bit bus res = 0..4097
# _CONFIG_BADCRES_12BIT_2S_1060US = const(0x0480)   # 2 x 12-bit sample average
# _CONFIG_BADCRES_12BIT_4S_2130US = const(0x0500)   # 4 x 12-bit sample average
# _CONFIG_BADCRES_12BIT_8S_4260US = const(0x0580)   # 8 x 12-bit sample average
# _CONFIG_BADCRES_12BIT_16S_8510US = const(0x0600)  # 16 x 12-bit sample average
# _CONFIG_BADCRES_12BIT_32S_17MS = const(0x0680)    # 32 x 12-bit sample average
# _CONFIG_BADCRES_12BIT_64S_34MS = const(0x0700)    # 64 x 12-bit sample average
_CONFIG_BADCRES_12BIT_128S_69MS = const(0x0780)   # 128 x 12-bit sample average

# _CONFIG_SADCRES_MASK = const(0x0078)              # Shunt ADC Res. &  Avg. Mask
# _CONFIG_SADCRES_9BIT_1S_84US = const(0x0000)      # 1 x 9-bit shunt sample
# _CONFIG_SADCRES_10BIT_1S_148US = const(0x0008)    # 1 x 10-bit shunt sample
# _CONFIG_SADCRES_11BIT_1S_276US = const(0x0010)    # 1 x 11-bit shunt sample
# _CONFIG_SADCRES_12BIT_1S_532US = const(0x0018)    # 1 x 12-bit shunt sample
# _CONFIG_SADCRES_12BIT_2S_1060US = const(0x0048)   # 2 x 12-bit sample average
# _CONFIG_SADCRES_12BIT_4S_2130US = const(0x0050)   # 4 x 12-bit sample average
# _CONFIG_SADCRES_12BIT_8S_4260US = const(0x0058)   # 8 x 12-bit sample average
# _CONFIG_SADCRES_12BIT_16S_8510US = const(0x0060)  # 16 x 12-bit sample average
# _CONFIG_SADCRES_12BIT_32S_17MS = const(0x0068)    # 32 x 12-bit sample average
# _CONFIG_SADCRES_12BIT_64S_34MS = const(0x0070)    # 64 x 12-bit sample average
_CONFIG_SADCRES_12BIT_128S_69MS = const(0x0078)   # 128 x 12-bit sample average

_CONFIG_MODE_MASK = const(0x0007)  # Operating Mode Mask
_CONFIG_MODE_POWERDOWN = const(0x0000)
_CONFIG_MODE_SVOLT_TRIGGERED = const(0x0001)
_CONFIG_MODE_BVOLT_TRIGGERED = const(0x0002)
_CONFIG_MODE_SANDBVOLT_TRIGGERED = const(0x0003)
_CONFIG_MODE_ADCOFF = const(0x0004)
_CONFIG_MODE_SVOLT_CONTINUOUS = const(0x0005)
_CONFIG_MODE_BVOLT_CONTINUOUS = const(0x0006)
_CONFIG_MODE_SANDBVOLT_CONTINUOUS = const(0x0007)

# SHUNT VOLTAGE REGISTER (R)
_REG_SHUNTVOLTAGE = const(0x01)

# BUS VOLTAGE REGISTER (R)
_REG_BUSVOLTAGE = const(0x02)

# POWER REGISTER (R)
_REG_POWER = const(0x03)

# CURRENT REGISTER (R)
_REG_CURRENT = const(0x04)

# CALIBRATION REGISTER (R/W)
_REG_CALIBRATION = const(0x05)
# pylint: enable=bad-whitespace


def _to_signed(num):
	if num > 0x7FFF:
		num -= 0x10000
	return num


class INA219:
	"""Driver for the INA219 current sensor"""
	def __init__(self, i2c_device, addr=0x40):
		self.i2c_device = i2c_device

		self.i2c_addr = addr
		self.buf = bytearray(2)
		# Multiplier in mA used to determine current from raw reading
		self._current_lsb = 0
		# Multiplier in W used to determine power from raw reading
		self._power_lsb = 0

		# Set chip to known config values to start
		self._cal_value = 4096
		self.set_calibration_32V_2A()

	def _write_register(self, reg, value):
		self.buf[0] = (value >> 8) & 0xFF
		self.buf[1] = value & 0xFF
		self.i2c_device.writeto_mem(self.i2c_addr, reg, self.buf)

	def _read_register(self, reg):
		self.i2c_device.readfrom_mem_into(self.i2c_addr, reg & 0xff, self.buf)
		value = (self.buf[0] << 8) | (self.buf[1])
		return value

	@property
	def shunt_voltage(self):
		"""The shunt voltage (between V+ and V-) in mVolts (so +-.327V)"""
		value = _to_signed(self._read_register(_REG_SHUNTVOLTAGE))
		# The least signficant bit is 10uV which is 0.00001 volts
		return value * 0.01

	@property
	def bus_voltage(self):
		"""The bus voltage (between V- and GND) in mVolts"""
		raw_voltage = self._read_register(_REG_BUSVOLTAGE)

		# Shift to the right 3 to drop CNVR and OVF and multiply by LSB
		# Each least signficant bit is 4mV
		voltage_mv = _to_signed(raw_voltage >> 3) * 4
		return voltage_mv

	@property
	def current(self):
		"""The current through the shunt resistor in milliamps."""
		# Sometimes a sharp load will reset the INA219, which will
		# reset the cal register, meaning CURRENT and POWER will
		# not be available ... athis by always setting a cal
		# value even if it's an unfortunate extra step
		self._write_register(_REG_CALIBRATION, self._cal_value)

		# Now we can safely read the CURRENT register!
		raw_current = _to_signed(self._read_register(_REG_CURRENT))
		return raw_current * self._current_lsb

	def set_calibration_32V_2A(self):  # pylint: disable=invalid-name
		"""Configures to INA219 to be able to measure up to 32V and 2A
			of current. Counter overflow occurs at 3.2A.
		   ..note :: These calculations assume a 0.1 shunt ohm resistor"""
		# By default we use a pretty huge range for the input voltage,
		# which probably isn't the most appropriate choice for system
		# that don't use a lot of power.  But all of the calculations
		# are shown below if you want to change the settings.  You will
		# also need to change any relevant register settings, such as
		# setting the VBUS_MAX to 16V instead of 32V, etc.

		# VBUS_MAX = 32V    (Assumes 32V, can also be set to 16V)
		# VSHUNT_MAX = 0.32 (Assumes Gain 8, 320mV, can also be
		#                    0.16, 0.08, 0.04)
		# RSHUNT = 0.1      (Resistor value in ohms)

		# 1. Determine max possible current
		# MaxPossible_I = VSHUNT_MAX / RSHUNT
		# MaxPossible_I = 3.2A

		# 2. Determine max expected current
		# MaxExpected_I = 2.0A

		# 3. Calculate possible range of LSBs (Min = 15-bit, Max = 12-bit)
		# MinimumLSB = MaxExpected_I/32767
		# MinimumLSB = 0.000061              (61uA per bit)
		# MaximumLSB = MaxExpected_I/4096
		# MaximumLSB = 0,000488              (488uA per bit)

		# 4. Choose an LSB between the min and max values
		#    (Preferrably a roundish number close to MinLSB)
		# CurrentLSB = 0.0001 (100uA per bit)
		self._current_lsb = .1  # Current LSB = 100uA per bit

		# 5. Compute the calibration register
		# Cal = trunc (0.04096 / (Current_LSB * RSHUNT))
		# Cal = 4096 (0x1000)

		self._cal_value = 4096

		# 6. Calculate the power LSB
		# PowerLSB = 20 * CurrentLSB
		# PowerLSB = 0.002 (2mW per bit)
		self._power_lsb = .002  # Power LSB = 2mW per bit

		# 7. Compute the maximum current and shunt voltage values before
		#    overflow
		#
		# Max_Current = Current_LSB * 32767
		# Max_Current = 3.2767A before overflow
		#
		# If Max_Current > Max_Possible_I then
		#    Max_Current_Before_Overflow = MaxPossible_I
		# Else
		#    Max_Current_Before_Overflow = Max_Current
		# End If
		#
		# Max_ShuntVoltage = Max_Current_Before_Overflow * RSHUNT
		# Max_ShuntVoltage = 0.32V
		#
		# If Max_ShuntVoltage >= VSHUNT_MAX
		#    Max_ShuntVoltage_Before_Overflow = VSHUNT_MAX
		# Else
		#    Max_ShuntVoltage_Before_Overflow = Max_ShuntVoltage
		# End If

		# 8. Compute the Maximum Power
		# MaximumPower = Max_Current_Before_Overflow * VBUS_MAX
		# MaximumPower = 3.2 * 32V
		# MaximumPower = 102.4W

		# Set Calibration register to 'Cal' calculated above
		self._write_register(_REG_CALIBRATION, self._cal_value)

		# Set Config register to take into account the settings above
		config = (_CONFIG_BVOLTAGERANGE_32V |
				  _CONFIG_GAIN_8_320MV |
				  _CONFIG_BADCRES_12BIT_128S_69MS |
				  _CONFIG_SADCRES_12BIT_128S_69MS |
				  _CONFIG_MODE_SANDBVOLT_CONTINUOUS)
		self._write_register(_REG_CONFIG, config)

	# def set_calibration_32V_1A(self):  # pylint: disable=invalid-name
	# 	"""Configures to INA219 to be able to measure up to 32V and 1A of
	# 	   current. Counter overflow occurs at 1.3A.
	# 	   .. note:: These calculations assume a 0.1 ohm shunt resistor."""
	# 	# By default we use a pretty huge range for the input voltage,
	# 	# which probably isn't the most appropriate choice for system
	# 	# that don't use a lot of power.  But all of the calculations
	# 	# are shown below if you want to change the settings.  You will
	# 	# also need to change any relevant register settings, such as
	# 	# setting the VBUS_MAX to 16V instead of 32V, etc.

	# 	# VBUS_MAX = 32V    (Assumes 32V, can also be set to 16V)
	# 	# VSHUNT_MAX = 0.32 (Assumes Gain 8, 320mV, can also be
	# 	#                    0.16, 0.08, 0.04)
	# 	# RSHUNT = 0.1      (Resistor value in ohms)

	# 	# 1. Determine max possible current
	# 	# MaxPossible_I = VSHUNT_MAX / RSHUNT
	# 	# MaxPossible_I = 3.2A

	# 	# 2. Determine max expected current
	# 	# MaxExpected_I = 1.0A

	# 	# 3. Calculate possible range of LSBs (Min = 15-bit, Max = 12-bit)
	# 	# MinimumLSB = MaxExpected_I/32767
	# 	# MinimumLSB = 0.0000305             (30.5uA per bit)
	# 	# MaximumLSB = MaxExpected_I/4096
	# 	# MaximumLSB = 0.000244              (244uA per bit)

	# 	# 4. Choose an LSB between the min and max values
	# 	#    (Preferrably a roundish number close to MinLSB)
	# 	# CurrentLSB = 0.0000400 (40uA per bit)
	# 	self._current_lsb = 0.04  # In milliamps

	# 	# 5. Compute the calibration register
	# 	# Cal = trunc (0.04096 / (Current_LSB * RSHUNT))
	# 	# Cal = 10240 (0x2800)

	# 	self._cal_value = 10240

	# 	# 6. Calculate the power LSB
	# 	# PowerLSB = 20 * CurrentLSB
	# 	# PowerLSB = 0.0008 (800uW per bit)
	# 	self._power_lsb = 0.0008

	# 	# 7. Compute the maximum current and shunt voltage values before
	# 	#    overflow
	# 	#
	# 	# Max_Current = Current_LSB * 32767
	# 	# Max_Current = 1.31068A before overflow
	# 	#
	# 	# If Max_Current > Max_Possible_I then
	# 	#    Max_Current_Before_Overflow = MaxPossible_I
	# 	# Else
	# 	#    Max_Current_Before_Overflow = Max_Current
	# 	# End If
	# 	#
	# 	# ... In this case, we're good though since Max_Current is less than
	# 	#     MaxPossible_I
	# 	#
	# 	# Max_ShuntVoltage = Max_Current_Before_Overflow * RSHUNT
	# 	# Max_ShuntVoltage = 0.131068V
	# 	#
	# 	# If Max_ShuntVoltage >= VSHUNT_MAX
	# 	#    Max_ShuntVoltage_Before_Overflow = VSHUNT_MAX
	# 	# Else
	# 	#    Max_ShuntVoltage_Before_Overflow = Max_ShuntVoltage
	# 	# End If

	# 	# 8. Compute the Maximum Power
	# 	# MaximumPower = Max_Current_Before_Overflow * VBUS_MAX
	# 	# MaximumPower = 1.31068 * 32V
	# 	# MaximumPower = 41.94176W

	# 	# Set Calibration register to 'Cal' calculated above
	# 	self._write_register(_REG_CALIBRATION, self._cal_value)

	# 	# Set Config register to take into account the settings above
	# 	config = (_CONFIG_BVOLTAGERANGE_32V |
	# 			  _CONFIG_GAIN_8_320MV |
	# 			  _CONFIG_BADCRES_12BIT_128S_69MS |
	# 			  _CONFIG_SADCRES_12BIT_128S_69MS |
	# 			  _CONFIG_MODE_SANDBVOLT_CONTINUOUS)
	# 	self._write_register(_REG_CONFIG, config)

	# def set_calibration_16V_400mA(self):  # pylint: disable=invalid-name
	# 	"""Configures to INA219 to be able to measure up to 16V and 400mA of
	# 	   current. Counter overflow occurs at 1.6A.
	# 	   .. note:: These calculations assume a 0.1 ohm shunt resistor."""
	# 	# Calibration which uses the highest precision for
	# 	# current measurement (0.1mA), at the expense of
	# 	# only supporting 16V at 400mA max.

	# 	# VBUS_MAX = 16V
	# 	# VSHUNT_MAX = 0.04          (Assumes Gain 1, 40mV)
	# 	# RSHUNT = 0.1               (Resistor value in ohms)

	# 	# 1. Determine max possible current
	# 	# MaxPossible_I = VSHUNT_MAX / RSHUNT
	# 	# MaxPossible_I = 0.4A

	# 	# 2. Determine max expected current
	# 	# MaxExpected_I = 0.4A

	# 	# 3. Calculate possible range of LSBs (Min = 15-bit, Max = 12-bit)
	# 	# MinimumLSB = MaxExpected_I/32767
	# 	# MinimumLSB = 0.0000122              (12uA per bit)
	# 	# MaximumLSB = MaxExpected_I/4096
	# 	# MaximumLSB = 0.0000977              (98uA per bit)

	# 	# 4. Choose an LSB between the min and max values
	# 	#    (Preferrably a roundish number close to MinLSB)
	# 	# CurrentLSB = 0.00005 (50uA per bit)
	# 	self._current_lsb = 0.05  # in milliamps

	# 	# 5. Compute the calibration register
	# 	# Cal = trunc (0.04096 / (Current_LSB * RSHUNT))
	# 	# Cal = 8192 (0x2000)

	# 	self._cal_value = 8192

	# 	# 6. Calculate the power LSB
	# 	# PowerLSB = 20 * CurrentLSB
	# 	# PowerLSB = 0.001 (1mW per bit)
	# 	self._power_lsb = 0.001

	# 	# 7. Compute the maximum current and shunt voltage values before
	# 	#    overflow
	# 	#
	# 	# Max_Current = Current_LSB * 32767
	# 	# Max_Current = 1.63835A before overflow
	# 	#
	# 	# If Max_Current > Max_Possible_I then
	# 	#    Max_Current_Before_Overflow = MaxPossible_I
	# 	# Else
	# 	#    Max_Current_Before_Overflow = Max_Current
	# 	# End If
	# 	#
	# 	# Max_Current_Before_Overflow = MaxPossible_I
	# 	# Max_Current_Before_Overflow = 0.4
	# 	#
	# 	# Max_ShuntVoltage = Max_Current_Before_Overflow * RSHUNT
	# 	# Max_ShuntVoltage = 0.04V
	# 	#
	# 	# If Max_ShuntVoltage >= VSHUNT_MAX
	# 	#    Max_ShuntVoltage_Before_Overflow = VSHUNT_MAX
	# 	# Else
	# 	#    Max_ShuntVoltage_Before_Overflow = Max_ShuntVoltage
	# 	# End If
	# 	#
	# 	# Max_ShuntVoltage_Before_Overflow = VSHUNT_MAX
	# 	# Max_ShuntVoltage_Before_Overflow = 0.04V

	# 	# 8. Compute the Maximum Power
	# 	# MaximumPower = Max_Current_Before_Overflow * VBUS_MAX
	# 	# MaximumPower = 0.4 * 16V
	# 	# MaximumPower = 6.4W

	# 	# Set Calibration register to 'Cal' calculated above
	# 	self._write_register(_REG_CALIBRATION, self._cal_value)

	# 	# Set Config register to take into account the settings above
	# 	config = (_CONFIG_BVOLTAGERANGE_16V |
	# 			  _CONFIG_GAIN_1_40MV |
	# 			  _CONFIG_BADCRES_12BIT_128S_69MS |
	# 			  _CONFIG_SADCRES_12BIT_128S_69MS |
	# 			  _CONFIG_MODE_SANDBVOLT_CONTINUOUS)
	# 	self._write_register(_REG_CONFIG, config)